Center punch gauge



Dec. 19, 1961 D. w. FAIRBANKS 3,013,340

CENTER PUNCH GAUGE Filed April 16, 1958 2 Sheets-Sheet 1 Flal l|llll llllll .55 35 2 INVENTOR- 17/? wow fiQ/RBHNKS BY 652a HTTOR/V Dec. 19, 1961 D. w. FAIRBANKS 3,013,340

CENTER PUNCH GAUGE Filed April 16, 1958 2 Sheets-Sheet 2 FIG. 6

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INVENTOR.

17H V/D WFAIRBANKJ United States Patent 3,013,340 CENTER PUNCH GAUGE David W. Fairbanks, 1 Dillon Road, New Rochelle, NY. Filed Apr. 16, 1958, Ser. No. 728,897 2 Claims. ((31. 33189) This invention relates to a center punch guage for accurately locating and impressing center punch mark upon flat machine or tool room work pieces in exact correspondence with the shop drawings.

The device of this invention comprises a squaring frame which provides two guideways, intersecting and overlapping each other at an angle of 90, each of said guideways slidably receiving a graduated blade, one of which constitutes a straight edge, the other supporting a guided center punch at its free end, the squaring frame having independent locking means to lock each blade and means thereon for reading the measurements on each blade, the straight edge blade having a stop member adjustable to either end thereof to engage an edge of the work piece adjacent to the straight edge thereof.

In the drawings:

FIG. 1 is a top plan view of the device.

FIG. 2 is a side elevation, including a section taken on line 2-2 of FIG. 1.

FIG. 3 is a rear elevation, including a section taken on line 3-3 of FIG. 1.

FIG. 4 is a side sectional elevation taken on line 44 of FIG. 1.

FIG. 5 is a top plan view of the squaring frame.

FIG. 6 is a side elevation taken on line 6-6 of FIG. 5.

FIG. 7 is a rear elevation taken on line 77 of FIG. 5.

Referring to the drawings:

Squaring frame A is of a general T shape and is recessed to provide two guideways, 10 and 20, intersecting and overlapping each other at an angle of 90 degrees, receiving blades B and C respectively, the bottom of guideway 10 lying in the same plane as the top of guideway 20.

Guideway 10 is defined by sidewall 11 having an inwardly turned lip 12 forming a channel section at that side, and by side wall 13, the width of the guideway providing a close sliding fit with blade B, sidewall 11 being longer than sidewall 13.

Guideway is formed in the wings A-1 and A4 of squaring frame A, intersecting guideway 10 directly beneath it at an angle of 90 and is defined on one side by side wall 21 having an inturned lip 22, and receives blade C.

A central longitudinal groove 23 is formed in blade C, which when blade C is inserted in guideway 20, is engaged by hooks 24 of truncated screw hooks 25 which extend through bores 26 in wings A-l, A-2, provided with knurled knobs 27 having threaded sockets. The truncated flat sides 28 of screws 25 are flush with the upper'surface of blade C, and are covered by wings A-1, A-2, thereby preventing the dislodgement of hooks 24 from groove 23. Blade C is locked in guideway 20 by screwing down knobs 27.

Screws 25 are equally spaced with reference to the median longitudinal line of blade C thereby enabling the portion of edge 29 of blade C opposed to side wall 21 of guideway 20 to be brought into and secured in absolute contact with side wall 21 for the full length of the latter, which is necessary to provide accurate squaring of blades B and C, and to maintain it during the use of the device against the impacts to which the device is subjected.

Blade B is locked in guideway 10 by screw 30 having a conical head 31 with a flat side 32, which is inserted from the top of wing A-2 of squaring frame A in bore 33 which is countersunk at 34 to receive conical head 31. Screw 39 is provided with a knurled knob having a ice threaded socket receiving the free end of the screw. Bore 33 is located close to the surface of side wall 13 of guideway 19, and screw 30 is adjusted in bore 33 so that fiat side 32 of conical head 31 is in alignment with the surface of side wall 13.

Upon screwing down knob 35, conical head 31 is drawn into countersink 34, thereby forcing flat side 32 of conical head 31 against the adjacent edge of blade B and forcing the latter against side wall 11.

The center line of screw 30 should be in alignment with the center of side wall 11, measured longitudinally, so that the pressure of fiat side 32 will be exerted on the portion thereof located centrally of side wall 11, whereby edge 40 of blade B will be brought into and secured in absolute contact with side Wall 11 throughout the length of side wall 11, in accordance with the principle hereinbefore stated with respect to the equal spacing of screws 25 with reference to the median line of blade C.

Blade C constitutes a straight edge, its upper edge 60 being placed against a straight edge of the work piece, with blade B lying fiat on the surface of the work piece. A stop member 45 is mounted at or near either end of blade C to engage a side of the work piece adjacent to its straight side, In the embodiment shown a transverse recess 46 is formed in the blade near each end thereof, to receive stop member 45, which is removably held therein by screw 47 inserted in a threaded bore extending through stop member 45 and into recess 46, screw 47 having a knurled knob 48.

Blades B and C are graduated. The scale shown in FIG. 1 is an inch scale but it may be a decimal or metric scale. For the purpose of clarity the graduations are shown in inch divisions, but actually they will be inch, which is about the smallest graduation that may be read without a Vernier. If finer graduations are desired, a Vernier could be added to the device, in which case a decimal scale would be used.

The upper numerals on the scale of blade C in FIG. 1 indicate measurements with reference to the zero point of the scale when stop member 45 is in the left hand position, and the lower reverse numerals refer to the reversed zero point when stop member 45 is in the right hand position.

A center punch guide 50 of truncated conical shape having a reduced end 51 is mounted on blade B near its upper end, through hole 52 in the latter, guide 50 being bored to receive punch 53 in a close sliding fit. Punch 53 has a central punching point 54 and a recessed flat portion 55. A threaded set screw 56 is extensible through a threaded bore in the wall of punch guide 50 opposite to the fiat 55, into the recess between flat 55 and the inner surface of said wall, which when adjusted prevents the removal of punch 53 from guide 50, but permits its movement within the vertical limits of said recess. Punch 53 is mounted so that punch point 54 is always in the vertical plane of the median longitudinal line of blade B, such median line bisecting guide 50.

The upper edge of blade B is squared and beveled to form a bevel edge 49 centrally located with respect to the median longitudinal line of blade B, the intersection of suchmedian line and bevel edge 49 being engraved on said bevel by line 5-7.

The free end of lip 12 of side wall 11 is beveled to provide a beveled edge 76' having a transverse engraved index line 71.

The graduations of the scale of blade B are read at index '71, the reading giving the distance of punch point 54 from edge 66 of blade C measured along the median longitudinal line of blade B. The location of index 71 is oifset from edge 60 of blade C, which is compensated by placing the zero point of the scale a like offset distance from the point on blade B corresponding to the position of punch point 54. This may be accomplished by setting the zero point of the scale at index 71 when punch point 54 is in exact registry with edge 60 of blade C, or by measurement. The upper right hand corner of lip 12, as shown in FIG. 1, is angularly set back from edge 60 of blade C to provide clearance for center punch guide 50, permitting it to be moved past edge 69 suificiently to enable punch point 54 to be placed in registry with edge 60.

The end of wing A4 is beveled to provide a beveled measuring edge 67 extending across the scale of blade C, normal thereto.

The graduations of blade C are read at bevel edge 67, the reading giving the measurement of the distance between the median longitudinal line of blade B and edge 65 when stop member is in the left hand position or edge 75 when it is in the right hand position.

Edge 65 is offset from the median longitudinal line of blade B, which requires a like offset of the zero point of the scale of blade C from edge 65 when stop member is in the left hand position or edge 75 when it is in the right hand position.

As seen in FIG. 1 the zero point of the scale of blade C is offset to the left of edge 65 a distance of 1 /2 inch which is the extent of the offset of bevel edge 67 to the left of the median longitudinal line of blade B. The distance between edge 65 in the left hand position of stop member 45 and edge 75 when in the right hand position is equal to the length of the scale employed, which in FIG. 1 is 12 inches, and blade C is extended at its right end a distance equal to said olfset.

In the use of the device of this invention, blades B and C are respectively set and locked at the coordinate measurements shown on the shop drawing, blade C, functioning as a straight edge, is placed against a straight edge of the Work piece with its upper edge 60 in contact there with and with stop member 45, in either its left or right hand position, in contact with an edge of the work piece adjacent to its straight edge, blade B resting flat on the surface of the work piece, and punch 64 is then tapped to impress the punch mark.

In cases Where the punch marks to be impressed upon the work piece extend for a distance exceeding the length of the scale of blade C, the device may be used by removing stop member 45. In such cases, parallel lines vertical to edge 60 of blade C are scribed on the work piece by chalk or otherwise, fixing the line position of the coordinate which otherwise would have been established by measurement on the scale of blade C. Blade C is moved along against the edge of the work piece until indeX line 57 is in registry with the applicable scribed line, blade B is then adjusted and set at the other coordinate measurement, and the punch mark is then tapped. Blade C is successively moved, index line 57 registered and blade B adjusted with respect to the other scribed lines, following the same procedure.

The structure of the device of this invention is such that no blind spot on the work piece is created in which punch marks cannot be impressed.

The drawings herein show one embodiment of my invention. Changes and modifications therein may be made without departing from the scope of this invention.

I claim:

1. A gauge and marking device for center-punching a work-piece having a straight edge and an edge adjacent thereto, comprising a squaring frame body having an upper and a lower guideway recessed therein, said upper guideway intersecting and overlapping said lower guideway centrally of the latter at an angle of degrees, the bottom of said upper guideway lying in the same plane as the top of said lower guideway, a blade having a graduated scale thereon and having a straight edge intended and adapted to abut the straight edge of the workpiece for the full length of said blade, a stop member removably mounted on said blade near an end thereof adapted to abut the other of said edges of the workpiece, a second blade having a graduated scale thereon and having a center punch guide mounted near its upper end centered on its median, a center punch slidably received by said center punch guide and extensible through said center punch guide and through said blade, said lower guideway slidably receiving said first blade, said upper guideway slidably receiving said second blade, and means for locking said blades in their said respective guideways at adjusted positions therein, said squaring frame body in the area thereof lying in the path of movement of said center punch guide being set back from said straight edge sutficiently to enable said punch point to be placed in registry with said straight edge.

2. A guage and marking device for center-punching a work-piece having a straight edge and an edge adjacent thereto, comprising a squaring frame body having a wide cross portion and a substantially narrower stern portion extending from said cross portion centrally thereof and at a right angle thereto, a lower guideway recessed in said cross portion and an upper guideway recessed in said stem portion intersecting and overlapping said lower guideway centrally thereof at a right angle thereto, the bottom of said upper guideway lying in the same plane as the top of said lower guideway, a blade having a straight edge intended and adapted to abut the straight edge of the work-piece for the full length of said blade and having a graduated scale thereon, a stop member removably mounted on said blade near either end thereof to abut the other of said edges of the work-piece, a second blade having a graduated scale thereon and having a center punch guide mounted near its upper end centered on its median, a center punch slidably received by said center punch guide and extensible through said center punch guide and through said blade, said lower guideway slidably receiving said first blade, said upper guideway slidably receiving said second blade, said squaring frame body in the area thereof lying in the path of movement of said center punch guide being set back from said straight edge sufiiciently to enable said punch point to be placed in registry with said straight edge, and means for locking said blades in their respective guideways at adjusted positions therein.

References Cited in the file of this patent UNITED STATES PATENTS 464,619 Wyatt Dec. 8, 1891 796,645 Herche Aug. 8, 1905 1,717,570 Lintner June 18, 1929 2,592,877 Ellington Apr. 15, 1952 2,830,378 Givan Apr. 15, 1958 

